The current revolution in wireless communications and the need for smaller wireless communications devices has spawned significant efforts directed to the optimization and miniaturization of radio communications electronic devices. Digital and analog components and circuits are included in silicon (Si) based integrated circuits (ICs) incorporated in these electronic devices. Passive components, such as inductors, resistors, capacitors and transformers, play a necessary role in the operation of these electronic devices, and thus efforts are directed toward reducing the size and improving the performance and fabrication efficiency of such passive components.
Existing technology provides a process of making spiral inductors which do not have any cores and are made with one single layer metal which is extremely thick which normally requires a 2 μm thickness to meet the Q factor. Moreover, the existing processes are complex and result in a thick metal inductor which is not ideal for current trends in miniaturization of electronic devices. Spiral core inductors having a core are produced with complex and less efficient processes and also result in metal inductors having a 3 μm thickness.
An example of existing damascene spiral transformer having vertically stacked spiral coils is shown in FIG. 1A. Spiral coils or metal lines 101 are laterally stacked over each other to form a spiral transformer. The spiral transformer has a pair of underpass contacts 103 and a pair of overpass contacts 105. A core including dummy lines 107 are present at the center region of the spiral inductor surrounded by the metal lines 101. During the etching of the dielectric 109, trenches are formed in the dielectric layer for both the metal lines 1 and the ferromagnetic core lines 107.
An example of existing damascene toroidal transformer with a ferromagnetic core is shown in FIG. 1B. The ferromagnetic strips 111 are formed within the dielectric layer of the core. The ferromagnetic strips 111 are formed using a damascene process and do not electrically contact the metal sections 113, 115. A dual-damascene Cu-process is used to fill the metal filled vias 117, and top Cu sections 115 are formed to close the toroidal coil loops.
A need exists for a less complex methodology enabling production of a single core inductor having a high quality Q factor and an ideal thickness for usage in semiconductor devices and the resulting device.